This invention relates to an agricultural implement including a central section and two wing sections arranged on respective sides of the central section for conjoint movement forwardly across the ground under motive power from a towing vehicle.
As agricultural implements of this type, for example cultivators, have become wider, they have incorporated a number of separate sections which must be connected together for conjoint movement but also must be articulated relative to one another to allow relative pivotal movement over uneven terrain.
In addition implements of this type must generally be folded in order to reduce them in width for transport from one location to another. It is known therefore to have an implement of this type which includes a central section having on either side a wing section where each wing section comprises an inner portion and an outer portion so that when folded the inner portion stands vertically above the outer sides of the central portion and the outer portion extends inwardly parallel to the central portion but spaced above.
The pivotal connection therefore between the central section and the inner wing section must be adapted to accommodate the articulation and also to accommodate this lifting movement.
In addition, a hitch arrangement must be provided which applies motive force to the central section and to the wing sections and yet again allows folding movement to obtain the transport position.
Various arrangements have been proposed for the pivotal couplings and for the hitch, however these are still open to simplification and improvement.
It is one object of the present invention, therefore, to provide an improved coupling arrangement of the above type.
According to the invention, therefore, there is provided a pull-type agricultural implement comprising a central frame section and two outer wing sections, the sections arranged in-line transverse to the direction of working motion of the implement, each section comprising a frame for supporting ground-working tools and ground wheels for carrying the frame across the ground, and pivotal coupling means for coupling an abutting end of each wing frame to a respective abutting end of the central frame, said pivotal coupling means including a lever, means mounting one end of the lever on the wing frame adjacent the abutting end thereof for pivotal movement about a horizontal axis, means mounting the other end of the lever on the central frame at a position inboard of the abutting end thereof for pivotal movement about a horizontal axis whereby the lever is free to lift in a vertical direction to allow the abutting end of the wing frame to lift and means on the central frame restricting the downward movement of the lever to limit the downward movement of the abutting end of the wing frame.
It is one advantage of the present invention therefore, that the coupling is provided by a lever which can lift and fall to provide the relative pivotal movement between the wing section and the central section and yet when it is desired to lift the wing section the lever is restricted in its downward movement by contact with the frame so that the wing section can be lifted about the pivot of the lever.
A second lever parallel to the first and similarly mounted can be included to provide spaced pivot points to more accurately control the movement of the wing section.
The hitch arrangement can include a central hitch portion for co-operating with the central frame section and two outer or wing hitch portions which are pivotally coupled to the central hitch portion so as to be foldable similarly to the wing sections themselves. Each wing hitch portion is attached to the respective wing section by a flexible chain which provides the necessary motive power and yet can accommodate any movement between the whole of hitch or the hitch portions and the wing sections. This arrangement allows the wing hitch portions to be effectively self-supporting, that is they are supported solely by the central hitch portion and by the chain without any necessity for ground wheels which add complication and expense.